Working of titaniferous metals



United States Patent 3,110,399 WORKING 0F TITANIFEROUS METALS Yves Georges Godron, Paris, France, assignor to Compagnie de St. Gobain, Paris, France No Drawing. Filed June 16, 1959, Ser. No. 820,581 Claims priority, application France June 20, 1958 7 Claims. (Cl. 207-10) on the hot metal, and which do not substantially attack the metal.

Another object is to provide titauiferous material, that is material containing a sutficient quantity of titanium to impart the qualities of titanium to the material, with lubrication useful in protecting it from the effect of friction during working at high temperature and pressure. Ordinary examples of such materials are titanium and titanium alloys, and ordinary examples of conditions of working them under heavy pressure at high temperature are the drawing, shaping, or extrusion of hot titaniferous bodies, for instance drawing or pressing hot titaniferous billets through dies. One known apparatus for such extrusion includes a strong cylindrical tube with a die at the end, into which the hot metal is inserted and through which it is forced, generating heavy friction against the die and the Wall of the tube.

Another object is to protect hot titaniferous material against the attack of gases such as those found in the atmosphere by means of a glass which does not substantially attack the material.

Titanium and its alloys at those temperatures employed for extrusion, for example about 950 C., are particularly susceptible to attack by gases in the air such as oxygen and water vapor. One may protect them by applying to the billet a coat of glass which also serves as a lubricant. The billets may be immersed in a bath of molten glass, withdrawn and heated to equalize their temperature until their entire mass is at the temperature chosen for extrusion, and then forced through the die aided by the lubricating effect of the adherent glass.

Glasses of the ordinary compositions are not useful either because their temperatures of softening do not permit proper lubrication of titanium under the conditions attending die extrusion or because during the equalizing of the temperature of the metal the molten glass detaches itself from the metal in part, or leaves the metal bare, or because these glasses attack the metal or lead an attack by bubbles released during the working.

These attacks on titanium and its alloys are important during extrusion because the billet, being imperfectly protected and lubricated in the cylinder of the press and in the die, is extruded with imperfections of surface.

The objects of this invention are to overcome or at least to materially reduce the imperfections referred to and they have been attained by the method of Working, and by the special lubricating glasses, herein disclosed. By

3,110,399 atented Nov. 12, 1963 "ice this invention, the titaniferous material is protected from attack by gases in the air, the glass lubricant itself does not substantially attack the material and does not generate corrosive gases at the temperatures and pressures of the working, and a satisfactory lubrication is secured at high temperature and high friction.

The objects were accomplished, in general, by the use of alkali borosilicate glass of which the viscosity at the temperature of working the titaniferous material under heavy pressure is in the range of l0 and 10 poises. In the preferred method of practising the invention the entire billet, while cold and before heating to working temperature, is provided with a coating of the lubricant glass, for example by being immersed in a bath of molten glass which is adherent to the billet, which does not substantially attack the metal, which forms a protective coat during heating, prevents gas attack on the hot titaniferous metal, and serves to lubricate during working without undergoing harmful disintegration. if necessary a complementary quantity of lubricant glass can be added for lubricating the die."

The new glasses of this invention have well defined compositions equivalent to the following:

SiO -25 to 48%, by Weight, B 0 10 to 32%. And preferably less than 45% of of the total weight of SiO and B203 Na O when excluding K 0 10 to 20%,

When K 0 is present between 0 to 18%, Na O is at maximum 20 to 5%, When K 0 is present between 18 to 45%, Na O is at maximum 5 to 0%, K 0 when excluding Na O 18 to 45 At least one of the group CaO,

BaO,MgO 3 to 17%, A1 0 0 to several percent, V 0 0 to several tenths of a percent.

When high percentages of alkali earth metal oxides are used it is preferable to use a mixture of them rather than CaO exclusively in order to guard against some possible devitrification during the heating which equalizes the temperature of the glass coated billet and brings it to working temperature.

If the glass contains BaO it should be somewhat more carefully fined than is necessary with other compositions in the foregoing table to be sure that CO has been expelled. Such methods of careful fining are classic and need no description. When such C0 bubbles form during the heating to equalize the temperature of the billet they may leave parts of the billet exposed, which may then suffer alteration.

Alumina A1 0 may be added in an amount between 0 and several percent by weight of the glass to increase viscosity. On the other hand, metal oxides that attack the titanium should preferably be avoided in the glass; examples are ZnO and 000.

If it is necessary to secure increased adhesion of the glass to the titan-iferous material a small amount, e.g. about 0.5%, of vanadium oxide can be added'to the 3 glass. However this may be accompanied by an oxidereduction reaction with the billet if the content is much more substantial.

The following examples A to G are given of the compositions of Various successful glasses falling within the scope of the invention, in parts by weight.

In carrying out the new method or use of these glasses the glass is melted, by heating until it melts, for example about 1300 C., the billet is coated with the glass, for instance by an immersion of the order of a minute in the glass about at 1200 C. and the glass coated billet is then heated to equalize its temperature in a furnace until it has reached working temperature throughout, which for extrusion would be, for example, about 950 C. The duration of this equalization of the temperature will depend on the size of the billet. The exterior appearance of the billet shows that the glass covers the surface of the metal, which is substantially not attacked, lacking those blackish spots which appear on billets, when the glass used is insufiiciently fined and contains important amounts of CO If a glass that seems to protect the billets effectively is too corrosive, it assumes a dark brownviolet colour by attacking the metal. If a glass protects insufliciently, or slips on the surface of the billets, this surface becomes badly oxydized during the equalizing of the temperature. Only a glass which does not substantially react on the billet will assure good lubrication and good protection. The glass covered billet may then be extruded with notable improvement, over the known processes of the prior art which use other glasses.

The improvement is so substantial that complicated shapes involving sharp edges and fine lines may be successfully extruded from titanium and its alloys.

As examples we have shown that when using glass F as a lubricant for extrusion of substantially pure titanium metal, and glass A for a titaniferous alloy containing about 92% Ti, the billets having been immersed about one minute in the melted glass, which was maintained at about 1200" C., and thereafter having been heated to equalize the temperature for about 45 minutes at about 900 C., and then having been extruded at about 900 C., superior results have been obtained compared to those obtainable with prior art glasses.

During the reduction in size of billets provided with a protective glass coat which also serves as a lubricant one may put a supplementary charge of lubricating glass between the coated billet and the die.

As many apparently widely different embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific examples hereinabove recited.

What is claimed is:

1. A method of protecting hot material of the class consisting'of titanium and its alloys against gas attack and friction during working, which comprises coating the said material with glass which does not substantially attack the said material, and which has the composition by weight 4 s10, 25 to 43%, B2( 3 t0 The B 0 preferably being less than 45% of the total weight of SiO and B 0 Alkali metal oxides 10 to 45 At least one of the group CaO, BaO,

MgO 3 to 17%,

A1 0 0 to several percent, V 0 0 to several tenths of a percent,

equalizing the temperature of the said material at working temperature and working the hot, glass-coated material.

2. A method of protecting a material of the class consisting of titanium and its alloys against gas attack and heavy pressure during working, which comprises coating the said material with glass which does not substantially attack the said material, and which has the composition by weight SiO 25 to 48%,

B 0 10 to 32%,

The B 0 being less than 45% of the total weight of SiO and B 0 Na O when excluding K 0 10 to 20%,

When K 0 is present between 0 to 18%, Na O is at maximum 20 to 5%, When K 0 is present between 18 to 45%, Na O is at maximum 5 to 0%, 0 when excluding Na O 18 to 45%, At least one of the group CaO, BaO,

MgO 3 to 17%, Al O 0 to several percent, V 0 0 to several tenths of a percent,

equalizing the temperature of the said material at Working temperature and working the hot, glass-coated material.

3. A method of protecting a material of the class con sisting of titanium and its alloys against gas attack and friction during working, which comprises coating the said material with glass which does not substantially attack the said material and which has the composition by weight:

sio 25 to 48%, B203 10 to 32%,

The B 0 being less than 45% of the total weight of SiO and B 0 equalizing the temperature of the said material at working temperature and working the hot, glass-coated material.

4. The method of lubricating a body o-f material of the class consisting of Ti and its alloys during working under heavy pressure, which consists in coating the body with a glass having the formula in parts by weight SiO about 30.4; B 0 about 21.4; CaO about 1 6.7 and K 0 about 31.5, heating the glass-coated body to working temperature, and the glass coat to a viscosity between 10 and 10 poises, and working the glass-coated body.

5. The method of lubricating a body of material of the class consisting of Ti and its alloys during Working under heavy pressure, which consists in coating the body with a glass having the formula in parts by Weight SiG about 41.5; B about 31.5; CaO about 6.3; MgO about 6.3 and No. 0 about 14.4, heating the glass-coated body to a working temperature; and the glass coat to a viscosity between and 10 poises, and working the glass-coated body.

6. The method of lubricating a body of material of the class consisting of Ti and its alloys during working under heavy pressure, which consists in coating the body with a glass having the formula in parts by Weight Si0 about 48.0; B 0 about 28; C210 about 6.0; MgO about 6.0 and Na o about 12, heating the glass-coated body to working temperature and the glass coat to a viscosity between 10 and 10 poises, and working the glasscoated body.

7. An alkali borosilicate glass for use as lubricant in the hot extrusion of a body made of titanium and its alloys which does not substantially attack the said hot titaniferous :rnetal during the equalization of the Working temperature of the material before extrusion, which has physical properties of Wettability, surface tension and viscosity enabling it to remain without gliding on the vertical walls of the body during the equalizing of temperature, and which has a viscosity of about 10 to 10 poises at a working temperature of about 950 0, having the following composition:

Si0 to 48%, e 0 10 to 32%,

The B 0 being less than of the total weight of SiO and E203,

No. 0 when excluding K O When K 0 is present between 0 to 18%, Na O is at maximum When K 0 is present between 18 to 45 Na O is at maximum K 0 when excluding Na O At least one of the group CaO,

5 to 0%, 18 to 45%,

B210, MgO 3 to 17%, A1 0 0 to several percent, V 0 not over several tenths of a percent.

References Cited in the file of this patent UNITED STATES FATENTS 7 OTHER REFERENCES Glastechnische Tabellen (Germany1932), by W. Eitel et al., page 687.

The Extrusion of Titanium, by A. M. Sabroif, W. M. Farris and P. D. Frost, WADC Tech. Report 54-555, March 1955, pages 1-68. 

1. A METHOD OF PROTECTING HOT MATERIAL OF THE CLASS CONSISTING OF TITANIUM AND ITS ALLOYS AGAINST GAS ATTACK AND FRICTION DURING WORKING, WHICH COMPRISES COATING THE SAID MATERIAL WITH GLASS WHICH DOES NOT SUBSTANTIALLY ATTACH THE SAID MATERIAL, AND WHICH HAS THE COMPOSITION BY WEIGHT 